The present invention relates to semiconductor devices, and in particular, testing fuse configurations in semiconductor devices.
A semiconductor device includes one or more integrated circuit (IC) devices, each of which includes many miniaturized circuits implemented in a single semiconductor substrate, commonly referred to as a “chip.” The IC devices are typically tested before they are used in order to ensure their proper operation. The IC devices can be tested in a limited fashion using built-in self test (BIST) circuitry that is implemented within the IC devices themselves. BIST testing however, is often incomplete and does not test all aspects of the device operation. Thorough testing of an IC device is traditionally accomplished with complex external testing equipment that typically requires many dedicated input/output (I/O) leads for allowing the test equipment to input various test patterns, codes, and data, and to stress the circuitry of the IC device. The use of the external testing equipment can be particularly difficult if multiple IC devices are combined within a single package that has a limited number of input/output leads, and a thorough test is required for one or more of the devices within the package.
Some IC devices include fuses that can be selectively and permanently “blown,” for example, by laser to optimize or fine tune certain electric or other operational parameters of particular device elements such as voltage regulators or delay elements. To find the optimal values of those electric or other operational parameters, such IC devices are traditionally tested for multiple fuse configurations in which different fuses are blown. Because the fuses are permanently blown in each of the different configurations, the traditional test requires different IC devices to implement different fuse configurations.